-, power station valve Valves to regulate the power station right to choose

-, power station valve Power station valves to correctly choose electric power is one of the most important energy industry, there are steam, wind, hydro, geothermal, tidal power, solar power, this kind of power station will have in common is that water into steam, use steam to drive steam turbine turns a generator to produce electric power, the difference is turning water into steam energy each are not identical. All kinds of plant structure is roughly same, simple view of power flow diagram is, in fact, water, steam cycle process, in this process to choose regulating valve is both simple and complex. Simple is simple process medium, only two kinds of water and steam, water is complex and steam temperature and pressure range is big, bring a series of problems such as: flashing, cavitation, erosion, corrosion, noise. But the first thing to consider is the safety and reliability of regulating valve. We according to the system to adjust the process that the valve selection. 1, the main water supply valve, vice boiler feed water valve, compound feed water regulating valve 'a'. Control requirements: control boiler into the water, to maintain the economic level and steam flow. b。 Working condition requirements: boiler pressure startup gate valve 100 - general 300 kilograms, flow is small, when normal operation of the pressure difference is small, large flow, flow adjustable ratio of 75:1 - 100:1. c。 Gate valve: the valve body is made of WCB/WC9, for double valves in the system startup valve requires the cavitation resistance, V level off, for compound feed water valve need to use characterization valve internal parts at the same time meet the needs of the boiler startup and normal operation. In the valve door choices for failure, ( Need to be aware of is generally for the water to remove dissolved oxygen will join diammonium for processing, it will be on the SATELLITE 6 alloy or other similar alloy adverse reaction, so it's best not to use 316 + STELLITE surfacing method processing valve internal parts, can be directly choose 416 stainless steel material) 。 2, boiler feed pump valve a minimum flow cycle. Control requirements: the boiler feed water pump start-up and safe operation and eliminating because flow is too small, temperature increase, water pump cavitation damage. ( Old minimum flow control valve with a switch mode power station, as well as the use of mechanical pump valve automatic cycle) 。 b。 Condition: the pressure drop of - 160 350 kilograms, is the largest power station in the system under pressure differential valve door, flow generally 30% of the normal flow. c。 Gate valve requirements: resistance to cavitation, block structure, grade V seal level, the pump start and stop running when the valve door work continuously, pump normal boot after valve door shut valve, the valve door is usually open for failure. 3, high/low heater drain valve feed water heater hydrophobic, condensed water heater drain a. Control requirements: control the location of condensed water heater, timely will be condensed water discharge, high water discharge, namely hydrophobic normal water level. b。 Condition: the medium is saturated water, heater control valve pressure difference between general is 6 - 30 kg, final stage drain valve connected directly to the condenser or deaerator. c。 Gate valve requirements: resistance to flash scour, V or VI levels of seal, valve door is usually open for failure. 4, deaerator water level control valve 'a'. Control requirements: provide traffic maintain the normal water level, deaerator eliminated by adding steam temperature gas dissolved in the water. b。 Condition: startup phase flow is small, the differential is bigger, normal flow, small pressure difference, working condition of similar feed water valve. c。 The valve door requirements: effective during low flow resistance to cavitation. 5, desuperheating valve ( Attemperator) 一个。 Control requirements: the high pressure water injection into the steam to steam temperature control requirements. b。 Condition: the medium is water, the pressure difference is bigger, the valve door requirements: a variety of types: type nozzle, auxiliary atomization type, self-contained type and type to the clamp. 6, reduction temperature and pressure relief valve ( High and low pressure bypass valve) 一个。 Control requirements: the high temperature and high pressure steam adjusting to a certain temperature and pressure; To the turbine to provide a bypass channel, boiler turbine and work independently. b。 Condition: high temperature and high pressure steam to reduce temperature and pressure relief. c。 The valve door requirements: thermal shock, noise reduction, response quickly.